Process for the preparation of colour images



1966 J. JAEKEN ETAL 3, I

PROCESS FOR THE PREPARATION OF COLOUR IMAGES 'Filed Feb. 5, 1964 3 Sheets-Sheet 1 DENSITY WAVELENGTH IN mp INVENTORS JAN JAEKEN MAURICE ANTOINE de RAMA/X WATSON.COLE,GRINDLE & WATSON ATTORNEYS Dec. 20, 1966 J. JAEKEN ETAL 3 ,293,032

PROCESS FOR THE PREPARATION OF COLOUR IMAGES Filed Feb. 5, 1964 3 Sheets-Sheet 2 DENSITY 1.00 20 1.0 so so 20 1.0 20

WAVELENGTH IN my FIG.2

INVENTORS JAN JAEKEN MAURICE ANTOINE de RAMA/X WATSON, COLE, GR/NDLE 8 WATSON ATTORNEYS Dec. 20, 1966 J. JAEKEN ETAL 3,293,032

PROCESS FOR THE PREPARATION OF COLOUR IMAGES Filed Feb. 5, 1964 3 Sheets-Sheet s 350 400 60 500 20 40 0 flfl 20 40 60 700 WI 'M/VGH/ m 0; IN VEN TOR5 17% Jae/762a BY Maw/ca Amw/ze de Pal/mix United States l atent C) 3,293,032 PROCESS FOR THE PREPARATION OF COLOUR IMAGES Jan Jaeken and Maurice Antoine de Ramaix, Hove, Belgium, assignors to Gevaert Photo-Producten, N.V., Mortsel-Antwerpen, Belgium, a Belgian company Filed Feb. 3, 1964, Ser. No. 342,305 Claims priority, application Great Britain, Aug. 2, 1961,

- 28,040/61 5 Claims. (Cl. 9622) The present application is a continuation-in-part of our application Ser. No. 213,165, filed July 30, 1962, now abandoned.

This invention refers to a process and a material for the Preparation of photographic reversal colour images.

As is known, the property of certain organic compounds to form a dye during the development of the exposed silver halide by coupling with the oxidized developing substance is the base of a process for subtractive colour photography. The organic compounds which form a dye by coupling with the oxidized developing substance are called colour couplers. In order to reproduce the visible light spectrum according to the subtractive process, a photographic colour material is usually composed of three silver halide emulsion layers which can be colour-developed and wherein on development are formed respectively according to the type of colour coupler, a yellow, a magenta and a cyan dye image. Each of the three silver halide emulsion layers is differently spectrally sensitized according to the absorption range of the dye to be formed. After :an image-wise exposure and development, such photographic material contains a complementary colour image (negative) which is used for the photographic printing of the positive colour image. This process is referred to as the negative-positive process.

For the simplification of the photographic reproduction process, a direct positive process is required. Rather early the principle of the reversal development was applied. According to such a process a photographic colour three-layer element as described above after imagewise exposure is developed with a black-and-white developer the oxidation products of which does not couple with the colour coupler present on the exposed parts of the photographic material. Next the photographic material is re-exposed to artificial light, and colour-developed, so that after the dissolution of the formed metallic silver by use of an oxidative bleaching and fixing bath, a direct positive colour image is obtained.

According to our invention a masking process is transformed in a process for preparing direct positive colour images.

In the U.S. patent specification No. 3,012,884, the U.S. patent specification No. 3,013,879, the Belgian patent specification No. 602,250 and the French patent specifications Nos. 1,275,271 and 1,291,076, an integral masking method is described which essentially consists in forming a colour image of a gradation opposite to that of the developed colour image after the usual colour development, by oxidatively coupling the residual colour coupler with an oxidatively coupling compound named masking compound. By choosing the masking compound in function of the colour coupler used, the unwanted side-absorption of the primarily formed dye image can be compensated by the secondarily formed dye image with opposite gradation. The compensation of the unwanted side-absorption of the primary image is based on the fact that the secondary image with opposite gradation absorbs the visible light in the region of the side-absorption of the primary dye image.

The oxidative coupling is normally carried out in an alkaline oxidative bleaching bath e.g., a potassium ferriice cyanide bleaching bath wherein the reduced silver metal is simultaneously dissolved.

As is well known, the quinone-imine dyes and azomethine dyes formed by coupling of the usual colourless couplers with an aromatic primary amino developing agent oxidized on development, can be destroyed by treatment with a strong acid. The dyes formed with these colour couplers by oxidative coupling with the oxidative coupling compounds mentioned in the above cited patents for an integral masking method, are strongly acidresistant. These proper-ties of both types of dyes have led to the development of a new process for preparing direct positive colour images.

For carrying out the process for obtaining a direct positive colour image according to this invention, a photographic material is used which contains at least one water-permeable colloid layer wherein light-sensitive silver halide grains are present and wherein said waterpermeable colloid layer or water-permeable colloid layer adjacent thereto contains at least one compound which on development in the exposed areas couples with an oxidation product of a developing agent to form on these areas a dye which can be destroyed or transformed in colourless product by a chemical treatment, and wherein the said water-permeable colloid layer containing the silver halide or a water-permeable colloid layer adjacent thereto also contains a compound which on treatment of the colour developed photographic element in an oxidizing solution oxidatively couples with said colourless compound to form in the non-developed areas a secondary dye which cannot be destroyed or transformed to colourless produots by the said chemical treatment for destruction or transformation of the primary dye.

The steps which are essential to the process for obtaining a direct positive colour image according to this invention are:

The exposure to an object of a photographic material composed as described above,

The development of the exposed photographic material in a colour-forming developer to form a primary dye on the exposed areas,

The bleaching of the colour developed photographic material with an oxidizing solution in order to remove the metallic silver formed on development and in order to form a secondary dye by oxidative coupling on the undeveloped areas,

A chemical treatment to destroy the primary dye leaving the secondary dye unaffected.

More particularly a process for preparing a direct positwo colour image has now been found, which comprises:

(1) Exposing to an object a photographic element comprising (a) at least one water-permeable layer which contains light-sensitive silver halide grains,

(b) a substantially colourless colour coupler in effective contact with said silver halide grains, said coupler being capable of forming on development a dye which by treatment with a strong acidic solution can be transformed in colourless products, and

(c) a compound in effective contact with said colour coupler, said compound being capable of forming an acid-resistant dye by oxidative coupling with said colour coupler,

(2) Developing the photographic element in a colour forming developer,

(3) Treating the photographic element in an oxidative bleaching bath,

(4) Treating the photographic element in a strong acidic solution,

(5) Fixing the photographic element not later than after step 4 but not before step 2, to produce:

colourless reaction products at the places where develepoment occurred, and a positive colour image of the object to be reproduced (formed by said oxidative coupling) at the non-developed areas of the photographic element Where colour coupler was still present after the development.

By effective contact of the colour coupler with the silver halide is to be understood that the oxidized developing agent formed by the reduction of the exposed silver halide can come into contact with the colour coupler in order to react therewith corresponding to the exposed areas.

By effective contact of the colour coupler with the oxidatively coupling compound is to be understood that the oxidatively coupling compound can oxidatively couple with the colour coupler in the colloid layer wherein the latter is present during the treatment in the oxidative bleaching solution. According to a preferred embodiment for preparing direct positive colour images according to this invention, this process comprises the steps of exposing to an object a photographic element containing a red-sensitive silver halide emulsion layer, a green-sensitive silver halide emulsi-on layer and a blue-sensitive silver halide emulsion layer, each of said layers containing a colour coupler capable of forming on deveolprncnt a dye which by treatment with a strong acidic solution can be transformed in colourless products, the red-sensitive emulsion layer also containing a compound which is capable of forming an acid-resistant cyan dye by oxidative coupling with the colour coupler present in that emulsion layer, the greensensitive emulsion layer also containing a compound which is capable of forming an acid-resistant magenta dye by oxidative coupling with the colour coupler present in that emulsion layer, the blue-sensitive emulsion layer also containing a compound which is capable of forming an acid-resistant yellow dye, byoxidative coupling with the colour coupler present in that emulsion layer devel oping the photographic element in a colour-forming developer, treating the photographic element in an oxidative bleaching bath, occasionally fixing the photographic element, treating the photographic element in a strong acidic solution containing at least one reducing agent or oxidizing agent, fixing the photographic element if not fixed before the acid treatment, finally rinsing and drying the photographic element, whereby a positive colour image is formed consisting of the superposed cyan, magenta and yellow dye separation images which are built up in the photographic element by the dyes formed on oxidatively coupling by treatment with the oxidative bleaching solution.

In principle all the colourless colour couplers described by C. E. Kenneth Mees in The Theory of the Photographic Process, revised edition, The Macmillan Company, New York, pp. 594-599, come into consideration for this process and more especially the colour couplers forming quinone-imine and azo-methine dyes on development with an aromatic primary amino developing agent. In practice, an acid-resistant, intense and sufliciently spectrally pure yellow, magenta and cyan dye has to be formed during the treating step with an oxidizing solution such as a photographic bleaching bath containing potassium ferricyanide.

As is known the class of the cyan colour couplers mainly consists of phenol and a-naphthol compounds which in the usual colour development with aromatic primary amino developing agents, eg N,N-d:iethyl-pphenylene diamine, form indo-phenol or quinone-imine dyes which are not completely acid-resistant. In the application of the process according to the present invention naphthol colour couplers are preferably used.

Suitable colour couplers for cyan to be applied in the process according to the present invention are described in the Belgian patent specifications Nos. 584,152, 584,846, 587,525, 590,934 and 595,694.

Naphthol colour couplers which are more particularly preferred correspond to the following general formula:

i l w Q son/r Y X represents an oxygen atom, a sulfur atom, a -NHCO group, a CONH group, a -SO NH group, a -NHSO group, a

wherein Z a sulphonyl group,

Y represents a hydrogen atom or a halogen atom,

D represents an aliphatic radical comprising a linear chain of at least 5 and at most 20 carbon atoms, preferably 14, 16 or 18 carbon atoms, and

M represents a hydrogen atom, an alkali metal atom or an ammonium group.

Suitable colour couplers of the above general formula are e.g.:

These colour couplers for cyan can be prepared e.g. by condensation of l-hydroxy-Z-naphthoic acid or one of its derivatives with one of the suitable aromatic amines according to German patent specification No. 1,121,061.

As most interesting representatives of the class of the magenta colour couplers to be applied in the process according to the present invention are mentioned compounds the active methylene group of which forms part of a pyrazolone ring system. On development with an aromatic primary amino developing substance these pyrazolone compounds form azo-methine dyes which are not very acid-resistant.

Suitable pyrazolone colour couplers to be applied in the process according to the present invention are described in the British patent specifications Nos. 502,665 and 636,988 and the US. patent application Ser. No. 314,806.

More particularly are mentioned pyrazolone colour couplers according to the following general formula:

wherein:

Ar represents a phenyl radical or a phenyl radical containing a solubilizing group such as a sulphonic acid group, and

D represents an aliphatic radical comprising a linear chain of at least 5 and at most 20 carbon atoms.

Especially useful in the process according to the present invention are the pyrazolone colour couplers of the 3-acylamino-Spyrazolone type which are preferably used in a form fast to diffusion, such as the colour couplers according to the general formula described in the US. patent application Ser. No. 314,806.

The class of the usual colour couplers for yellow comprises compounds containing an active methylene group in an open chain structure. On oxidatively coupling, with the greater part of the oxidatively coupling compounds more particularly described hereinafter, dyes are formed absorbing too much in the short wavelength range of the visible spectrum and also in the UV, range.

The colour couplers used in the present invention are preferably used fast to diffusion in a colloid layer such as a gelatino silver halide emulsion layer.

The usual terms colour couplers for yellow, magenta and cyan only refer to the colour formed during the primary colour development and do not apply to the colour obtained with these colour couplers after the oxidative coupling.

The oxidatively coupling compounds which come into consideration for being applied in the present invention are described in the patent specifications for an integral masking method. May be cited the 4-aminopyrazolone-3- compounds described in the US. patent specification No. 3,012,884 and the US. patent specification No. 3,013,879, and the amidrazone and hydrazone compounds described in the Belgian patent specification No. 602,250.

More particularly are cited the 4-aminopyraZolone-3- compounds corresponding to the following general formula:

wherein:

R represents a lower alkyl group e.g. a methyl group,

R represents a member selected from the group consisting of a lower alkyl group, e.g. a methyl group, and an aryl group, e.g. a phenyl group and a substituted phenyl p,

R represents an aliphatic radical rendering the molecule non-migratory and having more than 5 and less than 20 carbon atoms e.g. a member from the group consisting of a nonyl, an undecyl, a tridecyl and a pentadecyl group.

More particularly as amidrazone compounds are cited the compounds corresponding to the following general formulae:

R is a member selected from the group consisting of a hydrogen atom and an acyl radical,

R is a functional substituent of suflicient instability as to be capable of splitting off during oxidative coupling, said substituent being selected from the group consist- 6 ing of CONH and -SO X, wherein X is a member selected from the group consisting of a hydroxyl radi- I cal, an amino radical, a heterocyclic radical, an aliphatic hydrocarbon radical and an aryl radical, R is a member selected from the group consisting of a hydrogen atom, an alkyl radical and an aryl radical, R is a member selected from the group consisting of a hydrogen atom, an alkyl radical and an aryl radical, R is a member selected from the group consisting of a hydrogen atom, an amino radical, a heterocyclic radical, a hydrocarbon radical such as e.g. an alkyl radical, and an aryl radical, and Y represents the non-metallic atoms necessary to close a nitrogen-containing heterocyclic nucleus. More particularly as hydrazone compounds are cited the compounds corresponding to the following general formula:

wherein R represents a member selected from the group consisting of a hydrogen atom and an acetyl group,

R represents an unstable function-a1 substituent remaining intact during colour development but splitting off in the presence of said oxidizing solution, preferably a SO X radical, wherein X represents an organic radical comprising a linear chain of 5 to 20 carbon atoms,

R represents a member selected from the group consisting of an alkyl radical and an aryl radical, and

Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus containing 5-6 members, at least one of which is a nitrogen atom.

General Formula A:

N -NNHR wherein R' represents an unstable functional substituent remaining intact during colour development but splitting off in the presence of said oxidizing solution preferably a CONH or SO X radical wherein X represents a member selected from the group consisting of an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group, an aralkyl group and a substituted aralkyl group,

each of R' and R' (the same or different) represents a member selected from the group consisting of an alkyl radical, a substituted alkyl radical, an aryl radical, a substituted aryl radical, an aralkyl radical and substituted ralkyl radical, and

Z represents the necessary atoms to close a 6-membered aromatic nucleus or a substituted 6-membered aromatic nucleus e.g. a halogen substituted nucleus, an alkyl substituted nucleus, an arylamino substituted nucleus and an alkoxy substituted nucleus.

General Formula B:

RIIS

wherein R' represents an unstable functional substituent remaining intact during colour development but splitting off in the presence of said oxidizing solution, preferably a NH CO radical or a XSO radical wherein X represents a member selected from the group consisting of an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group, an aralkyl group and a substituted aralkyl group,

R" represents a member selected from the group consisting of an aryl group, a substituted aryl group, a heterocyclic radical, and a substituted heterocyclic radical,

R" represents a member selected from the group consisting of an alkyl group and a substituted alkyl group, and

Z" represents the necessary atoms to close a member selected from the group consisting of an aromatic nucleus or a substituted aromatic nucleus e.g. a halogen substituted nucleus, an alkyl substituted nucleus, an acylamino substituted nucleus, an alkoxy substituted nucleus, a sulfamyl substituted nucleus and an arylsulfonyl substituted nucleus.

Examples of compounds according to general Formula A with which good results are obtained are the following:

I CH

GHQ I N-NH-SO -(CHQ) ltOH I CH3 N-NH-S Oz-0 0 on I (OH2)14 C'H3 I /N o IOJN-NH-SO Q-o o 011 I (CH2)14 a 0 H3 111 JN-NH-SQQQ 0 OH I (CH2) 14- 3 I (C 11:):4-0 H;

OH Examples of compounds according to general Formula COOH ser f w mtg b NH--C O-CHz-CHz-O O OH PREPARATION 1 3 -methyl-tetrahydrobenzothiazo lane- 2 -n-h exadecylsulfonyl hydrazone 3.2 g. (0.010 mol) of n-hexadecylsulfonyl hydrazide, 25 0111. of benzene and 0.7 cm. (0.010 mol) of methylisothiocyanate are refluxed for 7 h. After cooling, sucking oil of the precipitate and recrystallization of methanol,

1 n hexadecylsulfonyl-4-methylthiosemicarbazide is obtained. Melting point: 174 C.

2.5 g. (0.006 mol) of this 1-n-hexadecylsulfonyl-4- methylthiosemicarbazide is heated for 1 h. at 120 C. in an excess (15 cm. of chlorocyclohexanone. The nonreacted chlorocyclohex-anone is distilled oil? under reduced pressure. The product left is washed with aceton-itrile and then recrystallized from acetonitrile. Melting point: 110 C. (with decomposition).

1 0 PREPARATION 2 [a-piperidin0 (m-methoxy-p-n-hexadecyloxy -benzaldehya'e] (p-carboxyphenyl sulfonyD-hydrazone CHz-CHg 7.5 g. (0.33 mol) of sodium are dissolved in 750 cm. of methyl Cellosolve (trade name for ethyleneglycol monomethyl ether). After addin 50 g. (0.33 mol) of 3- methoxy-4-hydroxy-benzaldehyde and refluxing the reaction mixture until complete dissolution of the reactants, g. (0.3 mol) of n-hexadecyl bromide are added drop- Wise. After further heating for 1.5 11., the reaction mixture is cooled and sucked off. The filtered crystals are then recrystallized from methanol yielding 86 g. of 3- methoxy-4-n-hexadecyloxybenzaldehyde. Melting point: 69 C.

A mixture consisting of 9.4 g. (0.025 mol) of this aldehyde, 1.2 g. of flowers of sulfur and 3.7 cm. (0.038 mol) of piperii'dine is heated for 6 h. on a water-bath. After cooling, the product obtained is ground under water, sucked 01f, Washed with Water and recrystallized from ethanol yielding 9.7 g. of 3-imethoxy-4-n-hexadecyloxythiobenzoylpiperidine. Melting point: 67 C.

A mixture consisting of 38 g. (0.08 mol) of this compound 16 cm. (0.24 mol) of methyl iodide and cm.-' of anhydrous acetone is refluxed for l h. After sucking off and washing with ether 41.5 g. of l-a-methy1thio-3 methoxy-4-n-hexadecyloxybenzylidene-piperidinium iodide are obtained. Melting point: 90 C. (with decomposition). On recrystallization the product is unstable.

6.17 g. (0.01 mol) of this compound dissolved in 50 cm. of pyridine are [allowed to react for 12 h. at room temperature with 2.16 g. (0.01 mol) of 4-carboxybenzene sulfonyl hydrazide. After pouring onto ice, sucking off, Washing With Water and recrystallization from acetonitrile, 3 :g. of [wpi'peridino (rn-methoxyp-n-hexadecycl- -oxy)-ben:z'aldehycle]- (poarboxy-phenyl-sulfonyl)4hydnazone [are obtained. Melting point: 108 C.

The 4-oarboxybenzene sulfonylhydrazi'de used in the latter preparation step is obtained by first dissolving 11 g. (0:05 mol) of 4-carboxybenzenesulfonyl chloride in 650 0111. of anhydrous ether and by adding thereto at 5 C. 6.5 can? of hydrazine. After washing the precipitate With cold ethanol, the obtained salt is boiled in ethanol and then ground under 5 N hydrochloric acid in order to set free the carboxylic acid from the hydrazinium salt. After recrystallization of this canboxylic acid from Water, 6 g. of 4-carboxybenzene sul-fionyl-hydnazide is obtained. Melting point: 235 C. with decomposition.

PREPARATION 3 (ix-morp'holino-o-chlorobenzaldehyde) -nhexadecylsulfonyl hydrazone OHr-CHz To a chilled solution of 6 g. (0.15 mol) of sodium hydroxide in 50 cm. of Water are firs-t added at 0 C. 11g. (0.125 mol) of morpholine and then at 0 to 5 C. 22 g. (0.125 mol) of o-chlorobenzoyl ch'lori'de. After the addition of the reactants, stirring is continued for /2 h. at the same temperature. The product formed is filtered 011 and washed with Water until neutnal. Recrystalliza- 1 1 tion from petroleum naphtha (boiling range: 90120 C.) yields 20 g. of 2-chloro-benzoylmorpholide. Melting point: 73 C.

14.5 g. (0.065 mol) of this Z-chlorobenzoylmorpholide are reacted =by refluxing for 40 min. with 5.8 g. (0.026 mol) of phosphonus pentasulfide in 65 cm. of pyridine. After pouring out the reaction mixture in ice, sucking off, Washing with Water and recrystallizing fnom ethanol, 11 g. of 2-chloro-thiobenzoylmorpholide are obtained. Melting point: 124 C.

11 g. (0.045 mol) of this 2-chloro-thiobenztoylmorpholi'de are refluxed for 1 h. with 8.8 cm. (0.15 mol) of methyl iodide in 40 cm. of anhydrous acetone. After coolin the formed reaction product is sucked off and Washed with ether to yield 16 g. of 4-(02-111fithYlthiO-2- chloro'benzy-lidene)-morpholinium iodide. Melting point: 152 C. (with decomposition). The product cannot be recrystallized because of its unstability.

16 g. (0.04 mol) of this morpholinium iodide are reacted at room tempenature for 48 h. with 11.5 g. (0.036 mol) of n-hexadecylsulfonyl hydrazide in 220 cm. of pyridine. The reaction mixture is poured into ice and the precipitate formed is sucked oft, washed with water and recrystallized t'rom n-hexane to yield 17 g. of (amonpholino-o-chlorobenzaldehyde)-n-hexadecyl sulfonyl hydrazone. Melting point: 75 C.

PREPARATION 4 3-ethyl-benz0thiaz0l0ne(2 -n-hexadecylsulfonyl hydrazone 38.6 .g. (0.2 mol) of 3-ethylbenzothiazolone-(2) hydrazone prepared according to K. Fuchs, Ber. 61 (1928) 59 and 32.4 g. (0.1 mol) of n-hexadecylsulfonyl chloride are refluxed for 2 hours with 600 cm. of .acetonitrile. The formed precipitate of hydrazone hydrochloride is sucked 01f While still warm, Whereafter the filtrate is cooled. A-t'ter recrystallization of the resulted crystals from methanol, 39 g. of '3-ethyl-henzo-thiazolone-(2)-n-hexadecylsulfon-yl hydrazone are obtained. Melting point: 115 C.

PREPARATION 5 J-phenyl-4-methyl-2-quin01011e-n-hexadecylsulfonyl hydrazone A mixture of 49.3 g. (0.21 mol) of 1-phenyl-4-methyl- 2-quin0lone prepared according to J. Gen. Chem. U.S.S.R. 21 (1951) 2221, 46.5 g. (0.21 mol) of phosphorus pentasulfide and 4-20 cm. of pyridine are refluxed for 2 h. Then the reaction mixture is poured on ice and the formed precipitate is recrystallized from isopropanol yielding 28.5 g. of '1-phenyl-4-methyl 2thioquinolone.

22.1 g. (0.088 mol) of this compound are dissolved in anhydrous acetone by heating and after adding 11 cm? of methyl iodide boiled for 5 min. The formed precipitate is sucked oif and washed with acetone yielding 32.7 g.

12 (0.083 mol) of 1-phenyl-4-methyl-2-methylmercapto quinolinium iodide. Melting point: 260 C. (with decomposition) Then a mixture of all this quantity of iodide, 26.6 g. (0.083 mol) of n-hexadecy-lsulfonyl hydrazide and 250 cm. of pyridine is heated for 5 days at 60 C. Thereupon the reaction mixture is poured on ice and the formed precipitate is recrystallized fmom acetonitrile yielding 29 g. of 11phenyl-4-rnethyl-2-quinolone-n-.hexadecylsulfonyl hydnazone. Melting point: 109 C.

PREPARATION 6 10-methyZ-9-acridan0ne-(2'-n-hexadecyloxy-5-carb0xyphenyD-sulfonyl hydrazone OOOH A mixture of 15.5 g. (0.074 mol) of N-methylacridone, prepared according to Gilman, J. Org. Chem. 17 (1952) 860, 465 cm. of pyridine and 10.3 g. (0.044 mol) of phosphorus pentasulfide is boiled for l h. After cooling, the reaction mixture is poured onto ice. The formed precipitate is sucked off, Washed with Water and recystallized from methyl Cellosolve yielding 12.5 g. of N-methylthioacndone. Melting point: above 260 C.

A mixture of 11 g. (0.049 mol) of this product, 18 cm. of methyl iodide and 2 l. of acetone is boiled for 1 h. By cooling, 7 g. of 9-methylmercapto-lO-methylacridinium iodide crystallize out. Melting point: above 260 C.

A solution of 1.8 g. (0.005 mol) of this iodide and 2.28 g. (0.005 mol) of 2-n-hexadecyloxy-5-carboxyphenyl sulfonyl hydrazide, prepared as explained below, in cm. of pyridine is allowed to stay for 60 h. at room temperature. After pouring out into water, the formed precipitate is sucked off, Washed with Water and recrystallized from acetonitrile yielding 1.5 g. of l0-methyl-9-acridanone (2-n-hexadecyloxy-5'-carboxyphenyl)-sulfonyl hydraz-one. Melting point: 170 C. (with decomposition).

The intermediate 2 n hexadecyloxy-S-carboxyphenyl sulfonyl hydrazide is prepared as follows:

A mixture of 1.5 1. of methyl Cellosolve, 58 g. of potassium hydroxide, 202 g. of 3-nitro-4-hydroxy methyl benzoate and 290 g. of n-hexadecyl bromide is refluxed for 6 h. After cooling, the formed precipitate is sucked off, Washed with water and recrystallized from acetonitrile yielding 285 g. of 3-nitro4-n-hexa-decyloxy methyl benzo- :ate. Melting point: 78 C.

84 g. (0.21 mol) of the above ester are refluxed for 1 h. in 500 cm. of N sodium hydroxide and 1000 cm. of ethanol, whereupon the solution is acidified with N-hydrochloric acid while being Warm. The formed precipitate is sucked off, Washed with Water until neutral, and recrystallized from acetic acid yielding 78 g. of 3-nitro- 4-hexadecyloxybenzoic acid. Melting point: 98 C.

A solution of 77 g. (0.19 mol) of this nitro compound in 1000 cm. of methanol are reduced under hydrogen pressure With Raney nickel as catalyst. The amine which crystallizes on cooling is recrystallized from methanol yielding 62 g. of 3-amino-4-hcxadecyloxybenzoic acid. Melting point: 100 C.

18.8 g. (0.05 mol) of this amine are dissolved in 250 cm. of warm dimethylsulfoxide. After adding 28.5 g. (0.15 mol) of p-toluene sulfonic acid the amine is diazotized at 2040 C. with 9 cm. of isoamylnitrite. After stirring for 1 h. the precipitated diazonium salt is sucked off and while still being wet added to 200-cm. of acetic acid which has been saturated with sulfur dioxide and to Which 4 g. of copper (II) chloride has been added. The temperature of the reaction mixture is kept for 1 h. at 40- 50 C. 9 g. of 2-hexadecyloxy-S-carboxyphenyl sulfonyl chloride are formed. Melting point: 90 C.

After recrystallizing from n-hexane the melting point rises till 92 C.

A solution of 11.5 g. (0.025 mol) of this sulfonyl chloride in 175 cm. of dioxane are added to a cooled solution of 6.25 cm. of hydrazine hydrate in 15 cm. of dioxan in such a way that the temperature is kept at 10 C. After 2 h. the formed precipitate is sucked off whereupon it is allowed to digest for 12 h. in 5 N hydrochloric acid.

The precipitate is recrystallized successively from ethanol and acetonitrile yielding 8.5 g. of 2-hexadecyloXy-5- carboxyphenyl sulfonyl hydrazide. Melting point: 141 C.

PREPARATION 7 1-metlzyl-2-o-chlorophenyZ-4-quinol0ne-n-hexade'cylsulfonyl hydrazone hydrochloride 11.3 g. (0.05 mol) of the ethyl ester of o-chlorobenzoyl acetic acid, 4.7 ccs. (0.05 mol) of aniline and 2 drops of concentrated hydrochloric acid are allowed to react for 6 days at 20 C. under vacuum in a desiccator containing sulfuric acid as desiccant. The reaction mixture is taken up into ether, washed with N hydrochloric acid and then with water and after drying over sodium sulphate evaporated till dry. After Washing with a little methanol 6.3 g. of the ethylester of ,B-anilino-o-chloro-cinnamic acid is obtained. Melting point: 94 C. After recrystallization from n-hexane the melting point is 96 C.

4.65 g. (0.015 mol) of the ester obtained are added to 50 cm. of diphenyl ether at 250 C. so that the formed ethanol is distilled off. After a reaction time of 15 min. the reaction mixture is allowed to cool. By the addition of ether the reaction product precipitates. Thereupon the precipitate is washed with ether, yielding 3.5 g. of 2-0- chlorophenyl 4 hydroxyquinoline. Melting point: 206 216 C.

18 g. (0.02 mol) of this quinoline are added to 38.5 0111. (0.42 mol) for phosphorus oxychloride. The solution formed is heated for 2 hours at 80 C. The reaction mixture is then poured onto ice, whereby an oil is formed which gradually becomes solid. After washing with water and recrystallization from ethanol 14.6 g. of 2 o-chlorophenyl-4-chloroquinoline are obtained. Melting point: 145 C.

5.48 g. (0.02 mol) of this quinoline derivative and- 11.2 cm. (0.12 mol) of dimethyl sulfate are heated for 2 hours at 120 C. After cooling the reaction mixture is washed with ether. The 9.9 g. of oil thus obtained (:1- methyl-Z-o-chlorophenyl-4-chloroquinolinium methyl sulfate) are used as such in the following reaction step without further purification.

9.9 g. of this quaternary quinoliniurn salt and 6.25 g. (0.02 mol) of n-hexadecylsulfonyl hydrazide are refluxed for 4 hours in 50 cm. of ethanol. After adding 50 cm. of an alcoholic solution of hydrogen chloride a crystalline precipitate is formed which is then washed with a little acetonitrile. After recrystallization from acetonitrile 4.9 g. 1 methyl 2-o-chlorophenyl-4-quinolone-n-hexadecylsulfonyl hydrazone hydrochloride are obtained. Melting point: 190 C. (with decomposition).

PREPARATION 8 I-methyI-2-phenyl-4-quin0l0ne-(2'-n-hexadecyl0xy-5'- carboxyphenyD-sulfonyl hydrazone COOH 87 cm. (0.5 mol) of the ethylester of benzoyl acetic acid, 47.6 cm. (0.5 mol) of aniline and 1 cm. of concentrated hydrochloric acid are allowed to react for 10 days at 20 C. under vacuum in a desiccator containing sulfuric acid as desiccant. The solid substance obtained is washed with a little methanol and recrystallized from methanol yielding g. of the ethylester of ,B-anilino-cinnamic acid. Melting point: 71 C.

27.5 g. (0.1 mol) of the latter ester are added to 350 cm. of diphenyl ether at 250 C. so that the ethanol formed is distilled off. After a reaction time of 15 min. the reaction mixture is allowed to cool whereupon the precipitate formed is sucked off and washed with ether. After recrystallization from ethanol 21 g. of 2-phenyl- 4-hydroxyquinoline are obtained. Melting point: 260 C.

6.63 g. (0.03 mol) of this quinoline are added to 8.25 cm. (0.09 mol) of phosphorus oxychloride. The solution formed is heated at 80 C. for 2 hours. Then ice is added to the viscous reaction mixture whereupon the precipitate formed is sucked off and washed with water. After recrystallizing from a mixture of ethanol and water, 4.75 g. of 2-phenyl-4-chloroquinoline is obtained. Melting point: 58 C.

4.75 g. (0.02 mol) of this quinoline derivative and 5.6 cm. (0.06 mol) of dimethylsulfate are heated for 2 hours at C. After cooling the reaction mixture is washed with ether. The 10 g. of oil l-methyl-2- phenyl-4-chlonoquinolinium methyl sulfate) thus obtained are used as such in the following reaction step without further purification.

18.25 g. (0.05 mol) of the above quaternary quinolini um salt and 22.8 g. (0.05 mol) of Z-n-he-xadecyloxy- 5-carboxyphenyl sulfonyl hydrazide are refluxed in 150 cm. of ethanol for 8 hours. After evaporation of the solvent, an oil remains consisting of hydrochloride from which the corresponding base is set free by the addition of 100 cm. of ammonium hydroxide. The oily base is washed With water, boiled in 200 cm. of methanol and cooled. In this wayv the base 1-methyl-2-phenyl-4-quinolone (2' n hexadecyloxy-S'-car boxyphenyl)-sulfonyl hydrazone is obtained in solid form. Melting point: C. After crystallization from acetonitrile the melting point is C.

PREPARATIONS 9-15 The compounds listed in the following table are prepared in an analogous way as the compounds of Preparations 7 and 8.

Prep Compound Melting point 9 CH 200 C. (with l decomposition).

I -H Cl NNH-SOz(CH2)15CH 10 CH; 160 C. (with decomposition). /N H;C-\

-H 01 I INHSOZ(CH2)15CH 11 CH 170 0. (with I decomposition). /N aC l I -H Cl N-NHSO2-( 2) w-CHa 12 CIJH 165 C.

/N H:C\ Q

NNHSOz-(OH2)15-CH;

13--. CH 95 C.

H CC H flT-NH-SOz-(C H2)15 CH3 H NNHSO2(CH2)15C H3 I NNHSOz(CH2)15CH3 PREPARATIONS 16 AND 17 65 and The two following compounds (311 0 H3 70 l I NHO O-OHa-OHz-COOH N NH-G OCHzCHz-CO0H are prepared starting from the nitro compounds of (11161171118 90ml 75 Preparations 14 and 15 respectively.

The nitro compound is converted into the corresponding amino compound by reduction in dioxan medium with Raney nickel as catalyst and under hydrogen pres sure. Thereupon an aquimolar mixture of the amino compound and succinic anhydride in aceto nitrile are refluxed for 1 hour yielding the desired compounds.

Depending on the structure of the colour coupler and the oxidatively coupling compound employed on the oxidative coupling there is formed a secondary acid-resisting yellow, magenta or cyan dye-image which is by that very fact of opposite gradation to that of the primary dye image formed on colour development and which is non acid-resistant, so that after the after-treatment with an acid, a positive dye image is left.

The yellow dyestuff of the positive image has preferably an absorption maximum between 430 and 480 mg.

The magenta dyestuff of the positive image has preferably an absorption maximum between 520 and 550 mg.

The cyan dyestufi of the positive image has preferably an absorption maximum between 610 and 680 mu.

The 4-aminopyrazolone-3 derivatives described in the present invention are preferably used for oxidatively cou pling with colourless colour couplers of the phenol and naphthol type to form a magenta dyestuff. With hydrazone compounds described in the present invention cyan,

18 magenta as well as yellow dyestuffs can be formed depending onthe type of the heterocyclic ring closed by Z and the type of the colour coupler used on oxidatively coupling viz. a colour coupler of the phenol or naphthol 5 type, a colour coupler with active methylene group such .as a pyrazolone colour coupler or a ketomethylene colour coupler for yellow. I

The amidrazone compounds described in the present inlvention are preferably used for oxidatively coupling with colour couplers of the phenol or naphthol type to form from yellow to magenta dyestufis.

FIGURES 1, 2 and 3 represent the absorption curves of a cyan dye, a magenta dye and a yellow dye respectively obtained according to the process described in Examples 8, 4 and 11 respectively. 1

To illustrate the possibility of obtaining from cyan to fyellow dyestuffs by using each time the same colourjc-ou- @pler but different oxidatively coupling compounds of the classes given above, the following Table 1 is given listing Ithe absorption maxima of the dyes obtained by oxidatively coupling of the naphthol colour coupler: N-(2-n- 5hexadecylsulfonyl-S-sulfophenyl)-1-hydroxy 2.- naphthoic acid amide with the oxidatively coupling compounds listed in said table. 7

' TABLE 1 Absorption max. Oxidatively coupling compound or maxima of the dye 1 (3H3 660 my.

i COOH \H/ N+NH-s0r- -(CHzhs-CHa 2..-- (Jets 620 and 660 mp.

IE-NH-SOr-(CHQrs-CHa a on: 01 620 and 660 Ill ,1. (ft-G 1 I NHS 02(CH2)t5-CHz 4 (31in 630 m...

N i i n-NHC O-(CH)1C 0 on I ji - i I;,NH-so2- oH2 15oH3 5 on. p 610 and 665 m...

I a NH-C O(CH2)2-COOH N- NH-so2(orr2 15oHa 6.-.. orlra 620 m...

I I-NHSO (OH2)15OHs TABLE ll-Continued Oxidativelj coupling compound Absorption max.

or maxima of the dye 1 N-NH-S 02-(CH2) 15-0 Ha COOH (If/Ha z)14G a 620 and 670 mp.

615 and 660 mp.

620 and 660 m TABLE 1C0ntinued Oxidatively coupling compound Absorption max.

or maxima of the dy TABLE '1COI1tinued Oxidatively coupling compound Absorption max. or maxlma of the dye To illusttate the possibility of obtaining from cyan to yellow dyestuffs by using each time the same oxidatively coupling compound but difierent colour couplers the following Tables 2 and 3 are given listing the absorption maxima of the dyes obtained 'by oxidatively coupling of the colour couplers listed in said tables with the oxidatively coupling compounds and 0 respectively. I

TABLE 2 Colour coupler Absorption maximum 1 ()H SO:-(CH2)15CH3 630 mg.

@0 ONE- 2 Sl0z(CHz)15CHa 505 111;:-

| so H l a 0 III H20 C-NH-C o- 3 S 475 mp.

HC CNHC-CHz-C O(CH2)15CHa H H H ll HOaS --C--N 0 O TABLE 3 Colour coupler Absorption maximum or maxima Colour coupler 1 of Table 2 620 (670) m Colour coupler 2 of Table 2 520 m Colour coupler 3 of Table 2 In Table 4 are listed the absorption maxima of dyes obtained by using further possible combinations of different colour couplers of the naphthol and pyrazolone type and oxidatively coupling compounds.

TABLE 4 Oxidatively Absorption Colour coupler coupling maximum compound or maxima of Table 1 IOH HaC-ITI(CH2) \5CH3 14 535 m C I I ONHT Idem 655 (620) my. Idem 8 630 my. Tdem 10 630 (660) m Tdem 9 660 (620) m (|)H 23 495 my.

0 ONE S 02NH(CH2)15CH3 Idem 25 490 m Idem 19 525 mp. Idem 21 525 m Idem 22 520 m Idem 16 550 my.

S|O H 18 450 my.

20 C(OH2)1BCH3 Idem 17 440 m Idem 14 420 m Idem-.- 7 500 m S|O2(CH2)1a-CH3 17, 450 my.

I N S 0 3H l H2O CNH-C 0Q Idem 11 450 m Idem 16 450 m Idem 440 m Idem 460 m Idem 13 445 my. Idem 5 510 mu. Idem 8 515 m Idem 4 505 m Idem 7 520 m Idem 10 515 m Idem 9 505 m Idem 2 505 m Idem 3 510 m To prevent the migration of the colour couplers and of the oxidatively coupling compounds from their respective emulsion layers, the colour couplers as well as the oxidatively coupling compounds are preferably of the nondiffusing type. Attention should, however, be drawn to the possibility that one common oxidatively coupling compound forming with three different colour couplers respectively a yellow, a magenta and a cyan dye can be applied in one of the processing baths or can be incorporated in the colour coupler containing silver halide emulsions in a form not necessarily fast to dififusion.

The ratio in mols of light-sensitive silver halide to colour coupler is preferably comprised between 6:1 and 15:1 and the ratio of colour coupler to oxidatively coupling compound preferably varies from 1:1 to 1:3.

A photographic multilayer material according to the present invention preferably contains the following elements: (1) a support, (2) a red-sensitized silver halide emulsion layer containing a colour coupler capable of forming on development a quinone-imine or azomethine dye and an oxidatively coupling compound which, after the development, on treatment with an oxidative bleaching bath, reacts with the residual colour coupler so as to form an acid-resisting cyan dye, (3) a green-sensitized silver halide emulsion layer containing a colour coupler capable of forming on development a quinone-imine or azomethine dye and an oxidatively coupling compound which, after the development, on treatment with an oxidative bleaching bath, reacts with the residual colour coupler so as to form an acid-resistant magenta dye, (4) a yellow filter layer consisting of a gelatin layer containing colloidal silver, and adjacent thereto, (5) a blue-sensitive silver halide emulsion layer containing a col-our coupler capable of forming on development a quinone-imine or ammethine dye and an oxidatively coupling compound which, after the development, on treatment with an oxidative bleaching bath reacts with the residual colour coupler so as to form an acid-resisting yellow dye. Usually the multilayer material also contains an anti-halation layer, a transparent protective layer and a subbing layer for anchoring the bottom emulsion layer on the support.

The colour couplers and the corresponding oxidatively coupling compounds can be present not only in their respective light-sensitive silver halide emulsion layers, but also in adjacent non light-sensitive colloid layers.

Although the process of forming direct positive colour images according to this invention preferably is carried out using a photographic colour material containing differently sensitized silver halide emulsion layers each containing a colour coupler and the corresponding oxidatively coupling compound, the process according to this invention can be applied with photographic materials containing mixed packet photographic silver halide emulsions such as described in the British patent specification No. 810,780, the French patent specification No. 1,258,509, the Canadian patent specification No. 518,723, the British patent specifications Nos. 786,274, 524,154, 524,555, 777,587, 755,987, 766,895, 718,404 and 793,570, the U.S. patent specifications Nos. 2,304,940, 2,284,877, 2,618,553, 2,893,867, and especially 2,168,182. In the latter U.S. patent specification a light-sensitive element is described for colour photography comprising a support and a plurality of differently sensitized emulsions colour couplers fast to diffusion and capable of forming dyes selected from the group consisting of quinone-imine and azomethine dyes with the oxidation products of a developer, at least one of said silver halide emulsions being applied in the form of a layer and at least one other of said emulsions being applied in the form of finely distributed hardened particles. Preferably according to this invention two differently sensitized emulsions, each of these containing respectively greenand red-sensitized silver halide, a colour coupler and an oxidatively coupling compound forming on oxidative coupling with containing said colour coupler respectively a cyan and a magenta dye, have been dispersed in the form of emulsion particles in a colloid layer onto which a yellow filter layer is coated whereon a blue-sensitive silver halide emulsion layer is coated containing a colour coupler and an oxidatively coupling compound forming a yellow dye with said colour coupler during treatment with an oxidizing solution.

The silver halide emulsions wherein the non-dilfusing colour couplers and the non-diffusing oxidatively coupling compounds are incorporated, contain the usual col- Ioids e.g. gelatin, polyvinyl alcohol, collodion or other natural colloids.

The silver halide emulsion layers can be coated onto a support of paper, glass, cellulose nitrate, organic cellulose esters e.g. cellulose triacetate, polyesters e.g. poly-' ethylene glycol terephthaliate, polymers e.g. polystyrene, or any other natural or synthetic plastic material.

On development, the used developing agents in principle should form with the colour couplers a non acid-resisting dye which can be destroyed in an acid containing bath. Preferably quinone-imine and azo-rnethine dyes are formed which as known are not very acid-resistant. Developing agents which come into consideration therefore are aromatic amino compounds e.g. mono-, diand triaminoaryl compounds, more especially N,N-dialkyl-pphenylenediamine and derivatives such as N,N-dialkyl- N'-sulphomethyl-p-phenylenediamine or N,N-dia1kyl-N- carboxymethyl-p-phenylenediamine. As monoamine developing agents, aminophenols and aminocresols, or their halogen derivatives, and also amin-onaphth-ols come into consideration.

The photographic bleaching bath wherein the oxidative coupling preferably takes place and wherein the metallic silver is reoxidized is an alkaline bleaching bath. It has preferably a pH of at least 8 and preferably contains as oxidizing compound potassium ferricyanide, and further salts e.g. borax, potassium bromide and magnesium sulphate.

The acid treatment which causes the destruction of the non acid-resistant quinone-imine and azomethine dyes which are formed on the exposed areas during the development step, is carried out in an acid solution having preferably a pH at least 1. The acid solution contains preferably a strong acid such as hydrochloric and/or sulfuric acid. It has been stated that the destruction of the primary dyes can be accelerated if an oxidizing agent such as potassium dichromate is also present in the acid solution. It has also been stated that the destruction of the primary quinone-imine or azomethine dyes is complete, even after short treatment if a combination is used of a strong acid and known-reducing agents or compounds which form in situ in an acid medium reducing substance.

Good results are obtained with an aqueous mixture of sulfuric acid, sodium sulfite and potassium iodide. Unexpectedly, basic substances such as quinoline are very well suited for preventing the reappearance of the colour after the acid treatment and rinsing. These substances are preferably added to a strong acid solution containing sodium sulfite and potassium iodide.

The photographic material used in the present invention can be fixed just after the colour development step, but normally has to be fixed also after the bleaching step for removing the oxidized silver metal.

The acid treatment is preferably carried out at room temperature. The destruction of the primary dyes proceeds very quickly in the mentioned compositions. In a few seconds the decolorization of the primary quinoneimine or azomethine dyes is complete.

It has further also been observed that for the bleaching of the primary quinone-imine and azomethiue dyes certain decolorizing baths applied in the Gasparcolor" process can be used wit-h good results. Some of these baths are described by Pierre Glafkides in Chimie Photogra- 29 phique, publication Photo-cinema Paul Montel, Paris, France, 2nd ed., p. 518.

The following examples illustrate the present invention.

Example 1 To 280 g. of a light-sensitive silver halide emulsion containing /6 mol of highly sensitive silver bromide and 8% of gelatin, are successively added: (1) 20 cm. of a 0.1% alcoholic solution of a sensitizing agent for green light, (2) 45 cm. of a colour coupler solution consisting of 4.5 g. of N-(2-n-hexadecylsulfonyl-5'-sulfophenyl)-1-hydroxy-Z-naphthoic acid amide sodium salt dissolved in a mixture of 40.5 cm. of water and 4.5 cm. of 2 N sodium hydroxide, and (3) 15 cm. of a solution consisting of 5 g. of the oxidatively coupling compound, prepared according to Preparation 2, dissolved in a mixture of 3 cm. of water, 2 cm. of sodium hydroxide and 2 cm. of ethanol. This emulsion is acidified with 8 cm. of N acetic acid and hardened with 1 cm. of a 10% aqueous chromic sulfate solution. After the addition of a little wetting agent, distilled water is added up to a total volume of 500 cm. 500 cm.

This emulsion is coated onto a cellulose triacetate support which has been provided with a usual subbing layer and dried.

A strip of the light-sensitive material obtained is exposed behind a grey-wedge and a green filter, and then developed for 10 min. at 20 C. in a developing bath of the following composition:

Then the developed material is rinsed for 10 min. with running water of 20 C. and bleached in an alkaline bleaching bath of the following composition:

Potassium ferricyanide grams 100 Potassium bromide do Magnesium sulfate do 50 Sodium hexametaborate do Water (pH:8.6) till cm. 1000 This film strip is then rinsed for 2 min. with running water of 20 C. and, for destroying the formed cyan quinonimine dye, treated for 10 min. in an acid bath of the following composition:

Potassium dichromate grams Concentrated hydrochloric acid cm. 50 Water up to cm. 1000 The film strip is then once more rinsed for 2 min. with running water of 20 C. and fixed in a fixing bath of the following composition:

Sodium thiosulfate anhydrous grams 200 Sodium bisulfite anhydrous do 25 Boric acid do 7.5 Potassium alum do 20 Sodium biacetate do 20 Water up to cm. 1000 The film strip is then rinsed for 2 min. with running water and dried.

On the film strip a positive magenta wedge image of high intensity is obtained having an absorption maximum at 530 mu.

Example 2 The light-sensitive material is prepared in an analogous way as that of Example 1 with the difference, however,

that the emulsion is not green-sensitized and that a same amount of the oxidatively coupling compound of Prepara- .-tion 3 is used instead of the oxidatively coupling compound of Preparation 2. After exposure behind a grey wedge to blue light and processing as in Example 1, a positive orange wedge image is obtained having an absorption maximum at 490 m Example 3 The light-sensitive material is prepared in an analogous way as that of Example 1 with the difference, however, that the emulsion is not green-sensitized, that the cyan color coupler N- (2'-n-hexadecylsulfonyl-S'-sulfophenyl 1-hyd1'oxy-2-naphthoic acid amide sodium salt is replaced by a same amount of the magenta color coupler 1-p-sulfophenyl-3-pentadecyl-pyrazolone-3 prepared according to British patent specification No. 502,665, and that the oxidatively coupling compound of Preparation 2 is replaced by a same amount of the oxidatively coupling compound of Preparation 4. After exposure behind a grey wedge to blue light and processing as in Example 1, a positive yellow wedge image is obtained having an absorption maximum at 430 mu.

Example 4 To 280 g. of a light-sensitive silver halide emulsion containing /6 mol of highly sensitive silver bromide and 8% of gelatin, are successively added: (1) 20 cm. of a 0.1% alcoholic solution of an optical sensitizer for green light, (2) 45 cm. of a color coupler solution consisting of 4.5 g. of N-(2'-n-hexadecylsulphonyl-5'-sulphophenyl)-1-hydroxy-2-naphthoic acid amide sodium salt dissolved in a mixture of 40.5 cm. of water and 4.5 cm. of 2 N aqueous sodium hydroxide, and (3) 6 g. of 1-phenyl-4-methyl-2-quinolone-n-hexadecylsulfonyl hydrazone prepared according to Preparation 5, dissolved by heating to 60 C. in a mixture of 60 cm. of diacetone alcohol, 12 cm. of 2 N aqueous sodium hydroxide and 48 cm. of water. This emulsion is acidified with N acetic acid to pH 7.5 and hardened with 1 cm. of 10% aqueous chromic sulphate. After addition of a little wetting agent, distilled water is added up till a total volume of 600 cm.

, This emulsion is coated onto a cellulose triacetate support which has been provided with a usual subbing layer and dried.

A strip of the light-sensitive material obtained is exposed behind a grey wedge and then developed for 10 min. at 20 C. in a developing bath of the following composition:

Sodium hexametaphosphate grams 2 Sodium carbonate anhydrous do 57 Sodium sulphite anhydrou "do--- 4 N,N-diethy-l-p-phenylene diamine hydrochloride do 3 Potassium bromide do 1 Hydroxylamine hydrochloride do 1.5 Water to cm. 1000 The developed material is then fixed in acid fixing bath of the following composition for 5 min. at 20 C Sodium hyposulfite anhydrous grams 200 Sodium bisulfite anhydrous -do 25 Boric acid do 7.5 Potassium alum 24 aq do 20 Sodium biacetate do 20 l The fixed material is then bleached for 5 min. at 20 C. 1n a bleaching bath of the following composition:

Potassium ferricyanide grams Potassium thiocyanate do 25 Ammonia water 25% cm. 25 Water to cm. 1000 The bleached material is then rinsed for 5 min. in running water of 20 C. and the negative colors are 31 bleached for min. in a color bleach bath of the following composition:

Sulphuric acid concentrated cm. 75 Potassium iodide grams Sodium sulphite anhydrous do 10 Quinoline do 50 Water to cm. 1000 The processed material is finally rinsed for 5 min. in running water of 20 C. and dried.

On the film strip a positive magenta wedge image of high intensity is obtained. Absorption maximum: 535 m, (see FIG. 2).

Example 5 The lightensitive material is prepared in an analogous way as that of Example 4 with the difference, however, that the emulsion is not green-sensitized and that the naphthol color coupler is replaced by a same amount of 1 (m sulfophenyl) 3 (m stearoylaminophenyl)-5- pyrazolone. After exposure behind a grey wedge to blue light and processing as described in Example 4, a positive yellow Wedge image is obtained on the film strip. Absorption maximum: 450 m Example 6 The light-sensitive material is prepared in an analogous way as that of Example 4 with the dillerence, however,

'that the emulsion is not green-sensitized and that the naphthol color coupler is replaced by a same amount of 1 (4 n hexadecylsulfonylphenyl) 3-(2-sulfobenzoylamino)-5-pyrazolone sodium salt. After exposure behind a grey wedge to blue light and processing as described in Example 4 a positive yellow wedge image is obtained on the film trip. Absorption maximum: 460 m Example 7 To /2 kg. of a red-sensitive silver bromo iodide (2% of iodide) emulsion containing V6 mol of silver halide is added a slightly alkaline alcoholic solution containing 10 g. of N-(2'-nhexadecylsulphonyl-S-sulphophenyl)-1- hydroxy-2-naphthoic acid amide sodium salt dissolved in a mixture of 7 cm. of 2 N aqueous sodium hydroxide and 193 cm. of water, and 5 g. of the oxidatively coupling compound corresponding to the following formula:

coon

Example 8 To 500 g. of a red-sensitized silver halide emulsion .containing 0.16 mol of silver halide (4 mol percent of silver iodide and 96 mol percent of silver bromide) and 80 g. of gelatin per liter digested for 1 h. at 36 C.,

.are successively added: (1) 250 cm. of distilled water, (2) 8 g. (12.5 millimol) of N-(2'-n-hexadecylsulfonyl- 5'-sulfophenyl)-1-hydroxy-2-naphthoic acid amide sodium salt dissolved in 80 cm. of 0.15 N sodium hydroxide, (3) 8 g. (13.2 millimol) of 1-methyl-2-(ochlorophenyl)- 4-quinolone-n-hexadecylsulfonyl hydrazone hydrochloride prepared as described in Preparation 7 and dissolved at 50 C. in cm. of ethanol. After neutralizing the emulsion with N acetic acid and after adding the usual ingredients such a stabilizing agents, surface-active agents and hardening agents, the emulsion is coated onto a transparent cellulose triacetate support provided with a gelatin subbing layer, in such a way that it covers 10 sq. m.

After drying the material is exposed to red light and processed as described in Example 1.

A positive cyan dye image with an absorption maximum: 655 mg is obtained (see FIG. 1).

Example 9 The composition of the silver halide emulsion is the same as in Example 8 except that the 8 g. of l-methyl- 2 ('o-chlorophenyl)-4-quinolone-n-hexadecylsulfonlyhydrazone hydrochloride are replaced by 8 g. of 1-methyl- 2 phenyl 4-quinolone-(2'-n-hexadecyloxy-5'-carboxyphenyl)-sulfonyl hydrazone prepared according to Preparation 8 and dissolved at 50 C. in 80 om. of 0.3 N potassium hydroxide in methanol.

After exposure and processing as indicated in Example 8 a positive dye image with absorption maxima: 620 (660) III/L is obtained.

Example 10 To 500 .g. of a green-sensitized silver halide emulsion containing 0.16 mol of silver halide (4 mol percent of silver iodide and 96 mol percent of silver bromide) and 80 g. of gelatin .per liter digested for 1 h. at 36 C. are successively added: (1) 250 cm? of distilled water, (2) 8 g. (12.5 millimol) of N-(2'-n-h-exadecylsulfonyl-5'-sulfophenyl)-1-hydroxy-2-naphthoic acid amide sodium salt dissolved in 80 cm. of 0.15 N sodium hydroxide, (3) 8 g. (26 millimol) of 1,2-dimethyl-4-amino-5-tridecylpyrazolone-3 dissolved in 80 cm. of methanol.

After neutralizing the emulsion with N acetic acid and after adding the usual ingredients such as stabilizing agents, surface-active agents and hardening agents the emulsion is coated onto a transparent cellulose triacetate support provided with a gelatin subbing layer in such a Way that it covers 1-0 sq. m.

After drying the material is exposed to green light and processed as described in Example 1.

A positive magenta dye image with absorption maximum: 540 m is obtained.

Example 11 The light-sensitive material is prepared in an analogous way as that of Example 4 with the difierence, however, that the emulsion is not green-sensitized, that the naphthol color coupler is replaced by a same amount of 1-(4-nhexadecylsulfonylphenyl) 3 (2-sulfobenzoylamin o)-5- pyrazolone sodium salt and that the oxidatively coupling compound of Preparation 5 is rep-laced by a same amount of the oxidatively coupling compound having the formula:

After exposure behind a grey wedge to blue light and processing as described in Example 4 a positive yellow wedge image is obtained on the film strip. Absorption maximum: 450 m (see FIG. 3).

Example 12 A photographic multilayer material is used for preparing direct positive color images. This multilayer material consists of the following superposed layers in the indicated sequence: a support, an anti halation layer, a gelatin layer, a red-sensitive halide emulsion layer containing as color coupler the sodium salt of N(2"-n-hexadecylsulfonyl-S'-sulfophenyl)-1-hydroxy-2-naphthoic acid amide and the oxdizinig coupling compound of Example 7, a gelatin interlayer, a green-sensitive silver halide emulsion layer containing the same color coupler as the redsensitive silver halide emulsion layer and the oxidizing coupling compound of Example 4, a yellow filter layer, a blue-sensitive silver halide emulsion layer containing as color coupler 1(p-sulfophenyl)-3-palmitoylamino S-pyrazolone and the oxidizing coupling compound of Example 4 and finally a gelatino antistress layer.

The red-sensitive emulsion layer is prepared as follows:

To 500 g. of a red-sensitized gelatino silver bromoiodide emulsion (2% iodide) containing mol of silver halide are added 10 g. of the sodium salt of N-(2'-nhexadecylsulfonyl-S-sulfophenyl)-1-hydroxy 2 naphthoic acid amide dissolved in a mixture of 7 cm. of 2 N aqueous sodium hydroxide and 193 cm? of water, and 5 g. of the oxidatively coupling compound corresponding to the following formula:

(IJOOH dissolved in a mixture of 12.5 cm. of 1 N aqueous sodium hydroxide and 37.5 cm. of Water. After acidification with acetic acid to pH 6 and after addition of the usual additives such as hardeners, wetting agents and stabilizers, the emulsion is coated.

The green-sensitive emulsion layer is prepared as follows:

To 500 g. of a green-sensitized gelatino silver bromoiodide emulsion (2% iodide) containing mol of silver halide are added: 9 g. of the sodium salt of N-(2'-hhexadecylsulfonyl 5' sulfophenyl)-1-hydroxy-2-naphthoic acid amide dissolved in a mixture of 81 cm. of water and 9 cm. of 2 N aqueous sodium hydroxide and 10g. of 1-iphenyl-4methyl-2-quinolone-n-hexadecylsulfonyl hydrazone prepared according to Preparation 5, dissolved by heating till 60 C. in a mixture of 100 cm. of diacetone alcohol, 10 cm. of 2 N sodium hydroxide and 80 cm. of water. This emulsion is acidified with N acetic acid to pH 7.5. After adding the usual additives such as hardeners, wetting agents and stabilizers, the emulsion is coated.

The blue-sensitive emulsion layer is prepared as follows:

To 500 g. of gelatino silver bromoiodide emulsion (2% iodide) containing mol of silver halide are added: 10 g. of the potassium salt of l-(p-sulfophenyD-3-palmitoylam-ino-Spyrazolone dissolved in a slightly alkaline mixture of alcohol and water, and 10 g. of 11phenyl-4- methyl-2-quinolone-n-hexadecylsulfonyl hydrazone prepared according to Preparation 5, dissolved by heating till 60 C. in a mixture of 100* cm. of diacetone alcohol, 10 cm. of 2 N sodium hydroxide and 80 cm. of water. This emulsion is acidified with N acetic acid to pH 7.5. After adding the usual additives such as hardeners, wetting agents and stabilizers, the emulsion is coated.

The obtained multilayer color material is exposed to a colored original and processed as described in Example 4. A positive color image of the original is obtained.

We claim:

1. A photographic process for preparing a direct positive colour image which comprises the steps of:

(1) exposing to an object a photographic element comprising (a) at least one water-permeable layer which contains light-sensitive silver halide grains,

(h) a substantially colourless colour coupler in effective contact with said silver halide grains, said coupler being capable of forming on development a dye which by treatment with a strong acidic solution can be transformed in colourless products, and

(c) a compound in effective contact with said colour coupler, said compound being capable of forming an acid-resistant dye by oxidative coupling with said colour coupler,

(2) developing the photographic element in a colour forming developer,

(3) treating the photographic element in an oxidative bleaching bath,

(4) treating the photographic element in a strong acidic solution, and

(5) fixing the photographic element no later than after said step 4, but not before said step 2, to produce:

colourless reaction products at the places where development occurred; and

a positive colour image of the object to be reproduced as a result of said oxidative coupling at the non-developed areas of the photographic element where colour coupler is still present after the development.

2. A photographic process for preparing a direct positive colour image according to claim 1, wherein the photographic element contains a red-sensitive silver halide emulsion layer, a green-sensitive silver halide emulsion layer and a blue-sensitive silver halide emulsion layer, each of said layers containing a colour coupler capable of forming on development a dye which by treatment with a strong acidic solution can be transformed in colourless products, the red-sensitive emulsion layer also containing a compound which is capable of forming by oxidative coupling with the colour coupler present in that layer an acid-resistant cyan dye, the green-sensitive emulsion layer also containing a compound which is capable of forming by oxidative coupling with the colour coupler present in that layer an acid-resistant magenta dye, and the blue-sensitive emulsion layer also containing a compound which is capable of forming by oxidative coupling with the colour coupler present in that layer an acid-resistant yellow dye, whereby a positive colour image is formed consisting of the superposed cyan, magenta and yellow dye separation images which are built up in the photographic element by the dyes formed on oxidatively coupling by treatment with the oxidative bleaching solution.

3. The process of claim 1 wherein said colour forming developer of step 2 comprises a primary amino developing agent and said colour coupler is capable of forming with said developing agent upon development therewith, a dyestuif selected from the group consisting of a quinone-imine and azo-methine dyestuffs.

4. The process of claim 1 wherein said compound of step (10) is selected from the group consisting of a 4- amino-pyrazolone-3 compound, a hydrazone compound, and an amidrazone compound.

5. A photographic process for preparing a direct positive colour image which comprises the steps of:

(l) exposing to a coloured object a photographic element containing a red-sensitive silver halide emulsion layer, a green-sensitive silver halide emulsion layer and a blue-sensitive silver halide emulsion layer, the red-sensitive silver halide emulsion layer containing a colourless naphthol colour coupler and in effective contact therewith a colourless quinolone- 4 hydrazone compound, the green-sensitive silver halide emulsion layer containing a colourless naphthol colour coupler and in eifective contact therewith a colourless 4-methyl-quinolone-2-hydrazone compound, the blue-sensitive emulsion layer containing a colourless 3-acylaminopyrazolone-5 colour coupler and in effective contact therewith a 

5. A PHOTOGRAPHIC PROCESS FOR PREPARING A DIRECT POSITIVE COLOUR IMAGE WHICH COMPRISES THE STEPS OF: (1) EXPOSING TO A COLOURED OBJECT A PHOTOGRAPHIC ELEMENT CONTAINING A RED-SENSITIVE SILVER HALIDE EMULSION LAYER, A GREEN-SENSITIVE SILVER HALIDE EMULSION LAYER AND A BLUE-SENSITIVE SILVER HALIDE EMULSION LAYER, AND RED-SENSITIVE SILVER HALIDE EMULSION LAYER CONTAINING A COLOURLESS NAPHTHOL COLOUR COUPLER AND IN EFFECTIVE CONTACT THEREWITH A COLOURLESS QUINOLONE4 HYDRAZONE COMPOUND, THE GREEN-SENSITIVE SILVER HALIDE EMULSION LAYER CONTAINING A COLOURLESS NAPHTHOL COLOUR COUPLER AND IN EFFECTIVE CONTACT THEREWITH A COLOURLESS 4-METHYL-QUINOLENE-2-HYDRAZONE COMPOUND, THE BLUE-SENSITIVE EMULSION LAYER CONTAINING A COLOURLESS 3-ACYLAMINOPYRAZOLONE-5 COLOUR COUPLER AND IN EFFECTIVE CONTACT THEREWITH A COLOURLESS 4-METHYL-QUINOLONE-2 HYDRAZONE COMPOUND, (2) DEVELOPING THE PHOTOGRAPHIC ELEMENT WITH AN AROMATIC PRIMARY AMINO DEVELOPING AGENT, (3) TREATING THE PHOTOGRAPHIC ELEMENT IN AN ALKALINE OXIDATIVE BLEACHING BATH CONTAINING POTASSIUM FERRICYANIDE, (4) TREATING THE PHOTOGRAPHIC ELEMENT IN AN ACID SOLUTION HAVING A PH OF AT LEAST 1, (5) FIXING THE PHOTOGRAPHIC ELEMENT TO PRODUCE: COLOURLESS REACTION PRODUCTS AT THE PLACES WHERE DEVELOPMENT OCCURRED, AND A POSITIVE COLOUR IMAGE OF THE OBJECT TO BE REPRODUCED AS A RESULT OF OXIDATIVE COUPLING OF COLOUR COUPLER STILL PRESENT AFTER DEVELOPMENT WITH THE RESPECTIVE HYDRAZONE COMPOUND IN EFFECTIVE CONTACT THEREWITH. 